-Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC) was used to quantify phytotoxins from plant tissues. Seed germination of P. paradoxa was reduced with the lowest concentration of the different extracts. However, the aqueous extract at 4% completely curtailed the germination of all the target species. In general, plant extracts had a concentration-dependent reduction of seedling growth of the target species. However, the ethanolic extract, at the lowest concentration, has stimulated the shoot length of both T. alexandrinum and T. aestivum, and the root length of the former. Mustard root exudates inhibited emergence and growth of the target species throughout the experiment. Ferulic and syringic acids were the dominant allelochemicals found when HPLC was used.Keywords: allelopathy, Brassica nigra, plant extracts, isothiocyanates (ITCs), phenolic acids.RESUMO -Experimentos de laboratório e estufa foram realizados para avaliar o efeito fitotóxico dos extratos de mostarda-preta e exsudatos de raiz de duas culturas: Trifolium alexandrinum e Triticum aestivum, bem como de duas plantas daninhas: Phalaris paradoxa e Sisymbrium irio. As sementes foram tratadas com extratos aquosos, etanólicos e clorofórmio por oito dias, ou submetidas a exsudatos de raiz de mostarda recém-colhidaem estufa durante cinco semanas. A cromatografia líquida de alto desempenho (HPLC) foi usada para a quantificação de fitotoxinas a partir de tecidos de plantas. Sementes de P. paradoxa apresentam germinação reduzida com a menor concentração dos diferentes extratos. No entanto, o extrato aquoso a 4% restringiu completamente a germinação de todas as espécies-alvo. Em geral, os extratos de plantas tiveram uma redução, dependendo da concentração do crescimento de mudas das espécies-alvo. No entanto, o extrato etanólico, na concentração mais baixa, tem estimulado o comprimento dos ramos de T. alexandrinum e T. aestivum e o comprimento da raiz da primeira. Exsudatos de raiz de mostarda inibiram o surgimento e crescimento das espécies-alvo durante todo o experimento. Os ácidos ferúlico e siringico foram os aleloquímicos dominantes encontrados utilizando HPLC.Palavras-chave: alelopatia, Brassica nigra, extratos vegetais, isotiocianatos (ITCs), ácidos fenólicos.

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We investigated the effect of plant growth‐promoting bacterial strains (PGPB) as biofertilisers on the grain metabolic composition of durum wheat (Triticum durum Desf.). To this aim, we conducted a greenhouse experiment where we grew durum wheat plants supplied with a biofertiliser consortium of four PGPB and/or chemical fertiliser (containing nitrogen, phosphorus, potassium, and zinc), under non‐stress, drought (at 40% field capacity), or salinity (150 mM NaCl) conditions. Nutrient accumulations in the grain were increased in plants treated with the biofertiliser consortium, alone or with a half dose of chemical fertilisers, compared to those in no fertilisation treatment. A clear benefit of biofertiliser application in the improvement of protein, soluble sugar, starch, and lipid contents in the grains was observed in comparison with untreated controls, especially under stress conditions. The most striking observation was the absence of significant differences between biofertiliser and chemical fertiliser treatments for most parameters. Moreover, the overall response to the biofertiliser consortium was accompanied by greater changes in amino acids, organic acids, and fatty acid profiles. In conclusion, PGPB improved the metabolic and nutrient status of durum wheat grains to a similar extent as chemical fertilisers, particularly under stress conditions, demonstrating the value of PGPB as a sustainable fertilisation treatment.

A comparative investigation of hydro-distilled essential oils from aerial parts of Mentha longifolia L. (ML), Mentha microphylla K.Koch (MM), Mentha australis R.Br. (MA), and Teucrium polium L. (TP) growing in Al Madinah Al Munawwarah, Saudi Arabia, was carried out. The total numbers of identified constituents were 22, 23, 14, and 20 in ML, MM, MA, and TP oils, representing 93.0, 99.3, 78.1, and 81.1% of the total oil composition, respectively. Pulegone (40.7%) and cineole (33.4%) were the major components in ML, whereas carvone (64.6%) was the major one in MM. Furthermore, β-linalool (22.9%) and α-terpineol (12%) were the major components in MA, whereas, (E)-3-caren-2-ol accounted for 12.1% in TP. The essential oils of TP and MA exhibited promising activities against Leishmania donovani promastigotes with IC50 values of 2.3 and 3.7 μg/mL, respectively. In contrast, MA essential oils exhibited antifungal activities towards Candida krusei and C. glabrata with IC50 values of 1 and 1.2 μg/mL, respectively.

Commiphora , myrrha, is a pantropical genus and perform well in arid and semi-arid environments. This genus has economic importance. Distribution of Commiphora species and their associated species in Saudi Arabia has not been studied to date. The current study report on (a) characterization and distribution of plant communities including Commiphora species and (b) assessment of factors influencing ecological preferences of these species. Five species of Commiphora are recorded inhabiting mountain slopes, steep escarpments or hills consisting of igneous rocks, either granites or basalt with drought prone shallow soil. One hundred and twenty-six plant species belonging to 95 genera and 35 families were found associated with different Commiphora species. Therophytes showed the most frequent life form class and Sudanian region elements recorded the highest phytogeographical units (28%) followed by Tropical elements. Field study showed that Commiphora gileadensis and C . quadricincta preferred granite and basalt rocks exposed to erosion, while C. myrrah , C. kataf and C. habessinica grow on resistant coarse pink granite. The analysis of 240 sampling stands with TWINSPAN revealed the vegetation of Commiphora habitats into eight vegetation groups; each group represented a distinct microhabitat. Dendrogram obtained from a hierarchical classification showed that habitats of C. gileadinsis and C. quadricincta are more similar than those of other species. This similarity was confirmed by Jaccard and Sorenson similarity indices and by Pearson correlation coefficient. This investigation compiled the information/data to facilitate future range management of Commiphora species.

Because sewage sludge is contaminated with heavy metals, its disposal in the soil may pose risks to the ecosystem. Thus, heavy metal remediation is necessary to reduce the associated risks. The goal of this research is to introduce a heavy metal resistant species and to assess its phytoremediation, oxidative damage markers and stress tolerance mechanisms. To this end, field research was done to compare the vegetation of polluted sites to that of a healthy site. We found 42 plant species identified in the study, Sesuvium portulacastrum L. was chosen because of its high relative density (10.3) and maximum frequency (100 percent) in the most contaminated areas. In particular, S. portulacastrum plants were characterized by strong Cu, Ni, and As uptake. At the organ level, to control growth reduction and oxidase damage, particularly in roots, increased detoxification (e.g., metallothionein, phytochelatins) and antioxidants mechanisms (e.g., tocopherols, glutathione, peroxidases). On the other hand, flavonoids content and the activity of glutathione-S transferase, glutathione reductase and dehydroascorbate reductase were increased manly in the shoots. These biochemical markers can be applied to select tolerance plant species grown under complex heavy metal contamination. Our findings also introduced S. portulacastrum to reduce soil contamination0associated risks, making the land resource available for agricultural production.

-Fayoum region is the most fertile agricultural land in Egypt and one of the oldest agricultural city in the world. The present study aimed to determine its weed flora composition and its distribution through different habitats. Results recorded 175 species of vascular plants belonging to 124 genera and 35 families distributed in eight habitats. The richest families were Poaceae, Asteraceae (Compositae) and Fabaceae (Leguminoseae), while genera with the highest number of species were Euphorbia, Amaranthus and Cyperus. Cynodon dactylon and Alhagi graecorum were the present species, recorded at all habitats. Old cultivated lands recorded the highest species number followed by orchard habitats, on the contrast road side and wasteland habitats recorded the lowest species numbers. Therophytes were the dominant life form, while Phanerophytes were the smallest group in this study, 5%. The highest Jaccard similarity index was recorded between healthy land and orchard habitats, which supported also by ward classification.Keywords: arable fields, weed, therophytes, agriculture, flora. Palavras-chave: terra arável, plantas daninhas, terófitos, agricultura, flora. RESUMO -A região de Faium é a área agrícola mais fértil do Egito e uma das mais

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